In order to assure a power source for a portable electronic device, such as a mobile phone, a secondary battery that enables performance of repetitive charge-discharge operations is used in the electronic device. A contactless charging system that enables recharging of the secondary battery without contacting the electronic device has been conceived as a system for recharging the secondary battery.
Such a contactless charging system has become prevalent primarily among devices, charging terminals of which are desired to avoid exposure, such as an electric shaver. Future proliferation of the contactless charging system in a device, such as a mobile phone, is conceived. Patent Documents 1 and 2 describe; for instance, a mobile phone adopting a contactless charging system.
In the event of occurrence of an anomaly in a secondary battery or an electronic device subjected to recharge or when these loads are not regular articles, an overcurrent or heating may arise. For these reasons, a contactless charging system that determines whether or not the load is a regular article is required. For instance, Patent Document 3 describes a power transmission apparatus that detects a change in the phase and amplitude value of a primary (charging) voltage attributable to a change in a secondary load (an object to be recharged) and that determines whether or not the load is a regular article.    Patent Document 1: JP-A-2005-143181    Patent Document 2: JP-A-2006-115562    Patent Document 3: JP-A-2006-230032